3Ware 9650SE-2LPML User Manual page 211

Scheduling page
The UDMA mode can become downgraded in the event that cable CRC errors
are encountered, requiring multiple retries to read sectors. In severe cases, the
UDMA mode may be downgraded from ATA 150 to ATA 133, to ATA 100, to
66, to 33.
This check is also done every time the system is booted.
This test checks to see whether SMART
Check SMART Thresholds.
thresholds have been exceeded.
The SMART thresholds indicate when a drive is likely to fail, based on the
number of errors that have been recorded through SMART (Self-Monitoring,
Analysis and Reporting Technology).
If any of the disk drives have detected a "threshold exceeded" condition, then
an AEN is logged to the 3DM Alarms page. Moreover, if anything unusual is
found during any self-test, it will be logged as an Alarm.
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